A grinder, especially a high precision grinder, for a bearing ring can have a ball-bearing race having a curved cross section is known comprising at least one tool support and at least one tool holder.
The tool holder is supported in the tool support on two identical feed guide rods held by a crosstie bar.
The grinder also includes a feed piston cylinder device for a feed and a withdrawal motion for a tool which works on the bearing ring or the ball-bearing race.
The tool support with the tool holder is oscillatable to and fro about a substantially central oscillation axis through the tool support which provides the tool being used mounted in the working position with a to and fro pivoting motion rotating substantially about the center of curvature of the curved cross section of the race.
Particularly our invention is relevant to a high precision grinder for a ball-bearing race with a ball groove curved in cross section. Of course the feed piston cylinder device provides the necessary pressing force for working the bearing ring. Grinding machines in which the tool performs the described pivoting motion when a ball-bearing race or a ball bearing outer ring is worked are described in a variety of German Patents, e.g. German patent Nos. 17 52 064 and/or 17 52 520.
In practice in the known grinders the feed guide rods are only held on one side by one crosstie bar. The feed piston cylinder device is eccentrically connected to this crosstie bar directed away from the tool holder. A considerable inertial force which causes a disturbing vibration and which can impair the precision of the grinding arises with the pivoting motion. The uniformity of the machined cross section can be adversely effected.